![]() ![]() Microscopic observation in a lab is required to distinguish between the two diseases.ĭue to the recent emergence of this fungus, fungicides labeled for Stigmina are rare however fungicides may still be used if registered for use on spruce in the state the tree is located. While more is to be learned about this disease, use the same timing recommended for Rhizosphaera. It too effects inner and lower needles and causes rows of black fungal structures on needles. Stigmina needle cast is a new disease of spruce readily mistaken for Rhizosphaera. Make the first application when new growth is between one-half and two inches long, usually in May, and a second application three to four weeks later. Treatment for two to three consecutive years may be needed. Fungicides labeled for spruce are effective if damage is not already too severe.įungicides must be applied during the spring infection period to work. Needles are infected in spring but symptoms do not become evident until a year later when needles turn reddish brown. Needle cast is most commonly seen on Colorado blue spruce since this species is overplanted. To confirm, fungal structures may be seen on affected needles with a hand lens as rows of black specks. On spruce, if two year old and older needles on the lower half of the tree have turned reddish brown, this could be Rhizosphaera needle cast. Now is the time to get up close and personal with your trees and look for symptoms to determine if fungicide use is justified. Since we’ve had a few years of good moisture, there is an increase in conifer diseases. Most fungal diseases require moisture on leaves or needles to cause an infection. While insecticides for bagworms should not be applied until June, April and May are the months to apply fungicides for control of the following diseases of pine and spruce. Also, clean-up of any infected needles and branches will help reduce the spread of the disease.Bagworms are not the only issue we are seeing in evergreens. Heavily infected trees may require several years of fungicide applications but should be sprayed, soil drenches are not effective. For Rhizosphaera needle cast, two properly-timed applications per year for at least two consecutive years, and sometimes three years, is required for control. Needle cast diseases can be effectively controlled with fungicides containing chlorothalonil. For best effectiveness, fungicides should be applied when the emerging needles are half elongated (1/2 to 2 inches in length). Protecting new growth as it emerges is very important. Young trees may be killed by this disease, but usually branches die off after 3-4 consecutive years of defoliation, causing trees to look disfigured.Įarly identification of Rhizosphaera can prevent major damage to individual trees and prevent the spread to nearby trees. It can take up to 15 months for the needles to show visible symptoms after the initial infection. It starts on the inner and lower growth and progresses upward through the tree. It is most common in trees growing outside of their native range. Rhizosphaera needle cast (Rhizosphaera kalkhoffii) is a foliar disease of spruce trees. ![]() Is there a chemical that can be placed on the ground to be absorbed by the tree?Īnswer: Thank you for contacting us regarding your tree issues. Also read about Spectro 90 copper based fungus control. ![]() I have read about the Needle Cast problem. Question: I have a blue spruce that is 40-years old and very tall. ![]()
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